Soybean prices fell to a decade-low on Tuesday after data pointed to a quickly advancing US harvest and as the Trump administration escalated trade tensions with the China, the largest destination for American exports of the legume.

China hit American soybeans with retaliatory import taxes in July after the Trump administration rolled out tariffs on $US50 billion worth of its goods. That country is the largest soybean customer in the world, using them in part to feed livestock. It imported nearly 60% of soybeans traded around the world in 2017.

Demand concerns come just after government data showed strong conditions for a record US harvest. A Department of Agriculture report out Monday said the soybean harvest was 6% complete, beating analyst expectations and doubling the five-year average.